Best company to mod your gear?

Try partsconnexion.com, they're still doing mods. I do lots of parts procurement with them.

Fine Tuned Audio / Video located in Winter Park Florida.....Kris Rhoades is the man. Visit his web site. 

I would proceed with caution regarding mods unless the modder has a track record with a particular piece of equipment. Like Modwright did for the Oppo DVD players. He’s perfected those mods and knows the end result.  Just replacing parts with more expensive ones may not result in what you’re after. Just my 2 cents based on past experience.